CN111201582B

CN111201582B - Input device

Info

Publication number: CN111201582B
Application number: CN201880065934.XA
Authority: CN
Inventors: 寒川井伸一
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 2017-11-10
Filing date: 2018-08-28
Publication date: 2023-07-28
Anticipated expiration: 2038-08-28
Also published as: CN111201582A; JP7028886B2; JPWO2019092953A1; US11366553B2; WO2019092953A1; DE212018000330U1; US20200264716A1

Abstract

An input device (100) according to an embodiment is provided with: a first sensor electrode (4) provided on the substrate (3); a second sensor electrode (6) disposed opposite to the first sensor electrode (4) and capacitively coupled to the first sensor electrode (4); and a detection circuit (5) that detects the approach of an operating body to the second sensor electrode (6) on the basis of the capacitance of the first sensor electrode (4).

Description

Input device

Technical Field

The present invention relates to an input device.

Background

Conventionally, an input device provided with a self-capacitance type touch sensor is known. The self-capacitance touch sensor includes a sensor electrode for detecting the proximity of the operation body, and detects the proximity of the operation body to the sensor electrode by using a change in capacitance of the sensor electrode.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2011-96369

Disclosure of Invention

Problems to be solved by the invention

The conventional input device includes a touch sensor and a housing that houses the touch sensor, and the touch sensor is disposed such that a sensor electrode provided on a substrate of the touch sensor faces a sensing region on the housing. Accordingly, the following problems exist: the larger the sensing area required for the input device, the larger the sensor electrode, resulting in an increase in the size of the substrate contacting the sensor and limitation of the layout on the substrate.

The present invention has been made in view of the above-described problems, and an object of the present invention is to miniaturize a sensor electrode of a self-capacitance type touch sensor.

Means for solving the problems

An input device according to an embodiment includes: a first sensor electrode disposed on the substrate; a second sensor electrode disposed opposite to the first sensor electrode and capacitively coupled to the first sensor electrode; and a detection circuit that detects the approach of the operation body to the second sensor electrode based on the capacitance of the first sensor electrode.

Effects of the invention

According to the embodiments of the present invention, the sensor electrode of the self-capacitance type touch sensor can be miniaturized.

Drawings

Fig. 1 is a perspective view showing an example of an input device according to a first embodiment.

Fig. 2 is a cross-sectional view taken along line A-A of the input device of fig. 1.

Fig. 3 is a diagram showing an example of a functional configuration of the detection circuit.

Fig. 4 is a flowchart showing an example of the operation of the input device.

Fig. 5 is a cross-sectional view showing a modification of the input device.

Fig. 6 is a perspective view showing an example of an input device according to the second embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in the description of the specification and drawings relating to the respective embodiments, the same reference numerals are given to the constituent elements having substantially the same functional structures, and overlapping descriptions are omitted.

< first embodiment >

Referring to fig. 1 to 5, an input device 100 according to a first embodiment will be described. The input device 100 according to the present embodiment is an input device for a user to input desired information by bringing an operation body close thereto, and includes a self-capacitance touch sensor for detecting the close of the operation body. The operation body is a conductive object used by a user to input information. The operation is, for example, a finger, but is not limited thereto.

First, the hardware configuration of the input device 100 is explained. Fig. 1 is a perspective view showing an example of an input device 100 according to the present embodiment. Fig. 2 is a cross-sectional view taken along line A-A of the input device 100 of fig. 1.

As shown in fig. 1 and 2, the input device 100 includes: the sensor includes a case 1, a support 2, a substrate 3, first sensor electrodes 4A to 4D, a detection circuit 5, and second sensor electrodes 6A to 6D. The substrate 3, the first sensor electrodes 4A to 4D, and the detection circuit 5 constitute a touch sensor 7. In the example of fig. 1, the support body 2 is omitted for easy observation of other structures.

Hereinafter, the upper and lower sides of the input device 100 will be described with reference to fig. 1 and 2, but the upper and lower sides of the input device 100 are not limited thereto. In addition, the first sensor electrodes 4A to 4D are not distinguished, and are referred to as first sensor electrodes 4. Similarly, the second sensor electrodes 6A to 6D are not distinguished, and are referred to as second sensor electrodes 6.

The case 1 is an exterior package of the input device 100, and houses the support 2, the substrate 3, the first sensor electrode 4, and the detection circuit 5. In the example of fig. 1 and 2, the housing 1 has a rectangular parallelepiped shape, and is divided into a lower housing 11 that constitutes a bottom plate of the housing 1, and an upper housing 12 that constitutes side plates and a top plate of the housing 1. The housing 1 is formed by integrating the lower housing 11 and the upper housing 12 by a method such as fitting, bonding, pressure bonding, welding, or the like. Further, the shape of the case 1 and the dividing method are not limited to the above examples.

The support body 2 is an arbitrary member or portion (for example, a portion integrally formed with the housing 1) that supports the substrate 3 so as to face the top plate of the housing 1. In the example of fig. 2, the support body 2 is provided on the upper surface of the bottom plate of the housing 1, but may also be provided on a side plate or top plate of the housing 1. Further, in the example of fig. 2, the support body 2 has a rectangular parallelepiped shape, but can be designed to be arbitrarily shaped to be able to support the substrate 3.

The substrate 3 is a printed substrate such as a rigid substrate or a flexible substrate, and constitutes the touch sensor 7 together with the first sensor electrode 4 and the detection circuit 5. The substrate 3 is supported by the support body 2 so as to face the top plate of the housing 1. Although not shown, wiring patterns for connecting the first sensor electrode 4 and the detection circuit 5 are formed on the upper and lower surfaces of the substrate 3. In the example of fig. 1 and 2, the shape of the substrate 3 in plan view is rectangular, but is not limited thereto.

The first sensor electrode 4 is a sensor electrode provided on the upper surface of the substrate 3 to detect the approach of the operator to the second sensor electrode 6, and is formed by a metal foil (copper foil or the like), a metal plate, or a plating layer. The first sensor electrode 4 is electrically connected to the detection circuit 5 via a wiring pattern provided on the substrate 3. Further, the first sensor electrode 4 is arranged to be opposed to the corresponding second sensor electrode 6. In other words, the substrate 3 is supported by the support body 2 so that the corresponding first sensor electrode 4 and second sensor electrode 6 face each other. In the example of fig. 1 and 2, the first sensor electrode 4A corresponds to the second sensor electrode 6A, the first sensor electrode 4B corresponds to the second sensor electrode 6B, the first sensor electrode 4C corresponds to the second sensor electrode 6C, and the first sensor electrode 4D corresponds to the second sensor electrode 6D. In the example of fig. 1 and 2, the shape of the first sensor electrode 4 in plan view is rectangular, but is not limited thereto. The input device 100 may include one or more first sensor electrodes 4.

The detection circuit 5 is a circuit for detecting the approach of the operation body to the second sensor electrode 6 based on the capacitance C of the first sensor electrode 4. The detection circuit 5 is, for example, one or more ICs (Integrated Circuit, integrated circuits), but is not limited thereto. The detection circuit 5 will be described in detail later.

The second sensor electrode 6 is a sensor electrode corresponding to a sensing region for detecting the proximity of the operating body, and is provided on the inner surface (lower surface of the top plate) of the casing 1, and is formed by a metal foil (copper foil or the like), a metal plate, or a plating layer. The second sensor electrode 6 is not connected to the first sensor electrode 4 or to the ground, and is disposed apart from the first sensor electrode 4 so as to face the corresponding first sensor electrode 4.

By configuring the second sensor electrode 6 in such a way, capacitive coupling of the corresponding first sensor electrode 4 with the second sensor electrode 6 occurs. As a result, when the operating body approaches the second sensor electrode 6, the capacitance C of the first sensor electrode 4 corresponding to the second sensor electrode 6 to which the operating body has approached changes. Therefore, the detection circuit 5 can detect the approach of the operating body to the second sensor electrode 6 based on the capacitance C. For example, when the operating body approaches the second sensor electrode 6A, the capacitance Ca of the first sensor electrode 4A corresponding to the second sensor electrode 6A changes, and therefore the detection circuit 5 can detect the approach of the operating body to the second sensor electrode 6A based on the capacitance Ca.

As in the examples of fig. 1 and 2, the second sensor electrode 6 is preferably formed larger than the first sensor electrode 4. Thus, the sensing area of the input device 100 can be enlarged without enlarging the first sensor electrode 4.

In the example of fig. 1 and 2, the shape of the second sensor electrode 6 in plan view is rectangular, but is not limited thereto. The input device 100 may include one or more second sensor electrodes 6. The distance L between the first sensor electrode 4 and the second sensor electrode 6 facing each other may be designed in accordance with the sensitivity required for the input device 100 and the sensitivity of the touch sensor 7. For the distance L, it is preferable that the higher the sensitivity required for the input device 100 is, the smaller the design is. Further, the higher the sensitivity of the contact sensor 7 is, the larger the distance L can be designed.

Next, the functional configuration of the detection circuit 5 will be described. Fig. 3 is a diagram showing an example of the functional configuration of the detection circuit 5. As shown in fig. 3, the detection circuit 5 includes a measurement unit 51 and a determination unit 52.

The measurement unit 51 is electrically connected to each of the first sensor electrodes 4 via a wiring pattern provided on the substrate 3, and measures the capacitance C of each of the first sensor electrodes 4. The measurement method of the capacitance C can be arbitrarily selected. The measuring unit 51 is configured by using a known circuit for measuring CR charge/discharge time, a circuit for transferring charged charges to a known capacitor, a circuit for measuring impedance, a circuit for measuring oscillation frequency by constituting an oscillation circuit, and the like. The capacitance C measured by the measuring unit 51 is input to the determining unit 52.

The determination unit 52 determines whether the operator approaches any one of the second sensor electrodes 6 or neither one of the second sensor electrodes is approaching, based on the capacitance C input from the measurement unit 51. The determination unit 52 may be realized by hardware or software. In the latter case, the determination unit 52 is configured by a microcomputer including a CPU (Central Processing Unit ), a ROM (Read Only Memory), and a RAM (Random Access Memory), and is realized by executing a program by the CPU. The determination method by the determination unit 52 will be described later.

Next, the operation of the input device 100 will be described. Fig. 4 is a flowchart showing an example of the operation of the input device 100.

First, the measurement unit 51 measures the capacitance C of each first sensor electrode 4 (step S101). Thus, the electrostatic capacitances Ca to Cd of the first sensor electrodes 4A to 4D are measured. The measurement unit 51 inputs the capacitance C obtained by the measurement to the determination unit 52.

Next, the determination unit 52 calculates a change amount C from the capacitance C input from the measurement unit 51 (step S102). Thus, the amounts of change Ca to Cd of the capacitances Ca to Cd of the first sensor electrodes 4A to 4D are calculated. The change amount C is a difference between the reference value of the capacitance C and the capacitance C measured by the measuring unit 51. The reference value of the capacitance C may be different for each first sensor electrode 4 or may be the same. The reference value of the capacitance C may be set in advance, or may be updated based on history data of the capacitance C.

Next, the determination unit 52 determines whether or not the calculated change amount c has a change amount c equal to or larger than the threshold cth (step S103). The threshold cth is a threshold value of the variation c set in advance to detect contact of the operating body. The threshold cth may be different for each first sensor electrode 4, or may be common.

When the amount of change c equal to or greater than the threshold cth does not exist (no in step S103), that is, when the amounts of change ca to cd are smaller than each of the threshold cth, the determination unit 52 determines that the operation body is not close to each of the second sensor electrodes (step S104).

On the other hand, when the change amount c equal to or larger than the threshold value cth is present (no in step S103), the determination unit 52 determines that the operation body is approaching the second sensor electrode 6 corresponding to the first sensor electrode 4 whose change amount c is equal to or larger than the threshold value cth (step S105). When there are a plurality of the amounts of change c equal to or greater than the threshold value cth, for example, the determination unit 52 may determine that the operating body is approaching the second sensor electrode 6 corresponding to the first sensor electrode 4 whose difference between the amount of change c equal to or greater than the threshold value cth and the threshold value cth is the largest. For example, the determination unit 52 may determine that the operating body is approaching the plurality of second sensor electrodes 6 corresponding to the plurality of first sensor electrodes 4 whose change amount c is equal to or greater than the threshold cth.

After the completion of step S104 or step S105, the determination unit 52 outputs the determination result (step S106). The determination result outputted by the determination unit 52 corresponds to the detection result based on the approach of the operating body of the detection circuit 5, and is inputted to a signal processing device or the like connected to the subsequent stage of the detection circuit 5.

The input device 100 detects the proximity of the operating body to the second sensor electrode 6 by executing the above operation for each predetermined time.

As described above, according to the present embodiment, the second sensor electrode 6 is increased, so that the sensing area of the input device 100 can be increased without increasing the size of the first sensor electrode 4. In other words, the first sensor electrode 4 required to achieve a desired sensing region can be miniaturized. This can reduce the size of the substrate 3 of the contact sensor 7 and improve the degree of freedom of layout on the substrate 3.

In addition, when the lower case 11 and the upper case 12 are assembled by disposing the substrate 3 at a predetermined position of the lower case 11 via the support 2 and disposing the second sensor electrode 6 at a predetermined position of the upper case 12, the substrate 3 can be disposed so that the corresponding first sensor electrode 4 and second sensor electrode 6 are opposed to each other with a predetermined distance therebetween. This can improve the assembling property of the input device 100.

Here, fig. 5 is a cross-sectional view showing a modification of the input device 100 according to the present embodiment. In the example of fig. 5, the second sensor electrode 6 is provided on the outer surface (upper surface of the top plate) of the housing 1. With such a structure, a decorative coating (a decoration formed by coating) provided on the outer surface of the input device 100 can be used as the second sensor electrode 6. Further, the operator can be in contact with the second sensor electrode 6. When the operating body contacts the second sensor electrode 6, the second sensor electrode 6 becomes a fixed ground potential, and therefore the detection circuit 5 can stably detect the proximity (contact) of the operating body. In addition, in the case where the decorative coating layer is connected to the ground as in the case of the vehicle-mounted product, even if the operation body is in contact with the decorative coating layer, the electrostatic capacitance of the decorative coating layer does not change, and therefore, the decorative coating layer cannot be used as the second sensor electrode 6. In this case, by connecting a diode between the decorative coating and the ground, the decorative coating can be used as the second sensor electrode 6.

In addition, although fig. 4 illustrates the method of determining the approach of the operation body by comparing the change amount c with the threshold cth, the method of determining the approach of the operation body by the determination unit 52 is not limited to this. For example, the determination unit 52 may determine the proximity of the operating body by comparing the capacitance C with a threshold value thereof, or may determine the proximity of the operating body based on the pattern of the capacitance C and the change amount C with time. The determination unit 52 can employ any determination method based on the capacitance C.

< second embodiment >

An input device 100 according to a second embodiment will be described with reference to fig. 6. Fig. 6 is a perspective view showing an example of the input device 100 according to the present embodiment. In fig. 6, the support body 2 is omitted for ease of viewing other structures. As shown in fig. 6, the input device 100 according to the present embodiment further includes third sensor electrodes 8A to 8D. The configuration and operation of the input device 100 according to the present embodiment are the same as those of the first embodiment except for the third sensor electrodes 8A to 8D. Hereinafter, the third sensor electrodes 8A to 8D will be referred to as third sensor electrodes 8 without distinction.

The third sensor electrode 8 is a sensor electrode corresponding to a sensing region for detecting the proximity of the operation body, and is provided on the same surface as the second sensor electrode 6 in the case 1, and is formed by a metal foil (copper foil or the like), a metal plate, or a plating layer. The third sensor electrode 8 is not connected to the first sensor electrode 4, as is the case with the second sensor electrode 6. On the other hand, the third sensor electrode 8 is electrically connected to the corresponding second sensor electrode 6 through a wiring formed of a metal foil (copper foil or the like), a metal plate, or a plating layer. Further, in the example of fig. 6, the third sensor electrode 8A corresponds to the second sensor electrode 6A, the third sensor electrode 8B corresponds to the second sensor electrode 6B, the third sensor electrode 8C corresponds to the second sensor electrode 6C, and the third sensor electrode 8D corresponds to the second sensor electrode 6D. Further, in the example of fig. 6, the shape of the third sensor electrode 8 in plan view is rectangular, but is not limited thereto. The input device 100 may include one or more third sensor electrodes 8.

With this structure, the third sensor electrode 8 is electrically connected to the second sensor electrode 6 capacitively coupled to the first sensor electrode 4. As a result, when the operating body approaches the third sensor electrode 8, the capacitance C of the first sensor electrode 4 corresponding to the third sensor electrode 8 to which the operating body approaches changes via the second sensor electrode 6. Therefore, the detection circuit 5 can detect the approach of the operation body to the third sensor electrode 8 based on the capacitance C of the first sensor electrode 4. For example, when the operating body approaches the third sensor electrode 8A, the capacitance Ca of the first sensor electrode 4A corresponding to the third sensor electrode 8A changes via the second sensor electrode 6A, and therefore the detection circuit 5 can detect the approach of the operating body to the third sensor electrode 8A based on the capacitance Ca.

The third sensor electrode 8 is preferably formed larger than the first sensor electrode 4 as in the example of fig. 6. This makes it possible to increase the sensing area of the input device 100 without increasing the size of the first sensor electrode 4.

Further, the third sensor electrode 8 is preferably formed larger than the second sensor electrode 6 as in the example of fig. 6. This can improve the degree of freedom in layout of the third sensor electrode 8 (sensing region).

Further, the second sensor electrodes 6 are preferably arranged adjacent to each other as in the example of fig. 6. Accordingly, when the operating body approaches the second sensor electrode 6, the respective capacitances C change substantially equally, and therefore the approach of the operating body to the second sensor electrode 6 and the approach of the operating body to the third sensor electrode 8 can be easily distinguished. For example, when there is only one change amount c equal to or greater than the threshold value cth, the determination unit 52 determines that the operating body is approaching the third sensor electrode 8 corresponding to the first sensor electrode 4 whose change amount c is equal to or greater than the threshold value cth; when there are a plurality of variations c equal to or greater than the threshold cth, it is determined that the operation body is close to the second sensor electrode 6. For example, when there are one or two of the amounts of change c equal to or greater than the threshold value cth, the determination unit 52 determines that the operating body is approaching the third sensor electrode 8 corresponding to the first sensor electrode 4 whose difference between the amount of change c and the threshold value cth is the largest; when there are three or more variations c of the threshold cth or more, it may be determined that the operating body is approaching the second sensor electrode 6. As a result, the approach of the operation body to the second sensor electrode 6 can be suppressed from being detected as a false detection of the approach of the operation body to the third sensor electrode 8.

As described above, according to the present embodiment, the third sensor electrode 8 can be arranged at any position that can be connected to the second sensor electrode 6 via the wiring. This can improve the degree of freedom in layout of the sensing region of the input device 100.

The present invention is not limited to the configurations shown here, such as the configurations shown in the above embodiments, or combinations of other elements. These aspects can be modified within a range not departing from the gist of the present invention, and can be appropriately determined according to the application mode thereof.

In addition, the international application claims priority based on the japanese patent application No. 2017-217673 filed on 10 th 11 th 2017, and the entire contents of the application are incorporated by reference into the present international application.

Symbol description

1: shell body

2: support body

3: substrate board

4: first sensor electrode

5: detection circuit

6: second sensor electrode

7: contact sensor

8: third sensor electrode

11: lower shell

12: upper shell

100: an input device.

Claims

1. An input device, wherein,

the device is provided with:

a first sensor electrode disposed on the substrate;

a second sensor electrode which is not connected to the first sensor electrode or to ground, and is disposed apart from the first sensor electrode so as to oppose the corresponding first sensor electrode, and is thereby capacitively coupled to the first sensor electrode; and

and a detection circuit electrically connected to the first sensor electrode via a wiring pattern provided on the substrate, and detecting the approach of the operation body to the second sensor electrode based on the capacitance of the first sensor electrode.

2. The input device of claim 1, wherein,

the second sensor electrode is larger than the first sensor electrode.

3. The input device according to claim 1 or 2, wherein,

the second sensor electrode is provided in a case that houses the substrate.

4. The input device according to claim 3, wherein,

the second sensor electrode is disposed on an inner surface of the housing.

5. The input device according to claim 3, wherein,

the second sensor electrode is disposed on an outer surface of the housing.

6. The input device according to claim 1 or 2, wherein,

the second sensor electrode is formed by plating.

7. The input device according to claim 1 or 2, wherein,

the detection circuit determines that the operating body is approaching the second sensor electrode disposed opposite to the first sensor electrode when the amount of change in capacitance of the first sensor electrode is equal to or greater than a threshold value.

8. The input device according to claim 1 or 2, wherein,

the input device further includes: and a third sensor electrode electrically connected to the second sensor electrode.

9. The input device of claim 8, wherein,

the third sensor electrode is larger than the first sensor electrode.

10. The input device of claim 8, wherein,

the third sensor electrode is larger than the second sensor electrode.

11. The input device of claim 7, wherein,

a plurality of the second sensor electrodes are adjacently disposed.

12. The input device of claim 8, wherein,

the detection circuit determines that the operating body is in proximity to the third sensor electrode electrically connected to the second sensor electrode disposed opposite to the first sensor electrode when the amount of change in capacitance of the first sensor electrode is equal to or greater than a threshold value.